High-Pressure Mass Spectra and Ion Chemistry of Carbon Dioxide

Abstract

A mass-spectrometric study of ion–neutral reactions occurring in CO2 subjected to electron impact yields rates in agreement with previous studies for reaction of C+ and O+ with CO2. Charge transfer from O+ to CO2 is believed to compete with formation of O2+ in these experiments. Reaction of CO+ with CO2 is found to be somewhat faster than previously reported. An approximate rate has been obtained for loss of CO22+. The great abundance of C2O4+ in this system at pressures near 1 torr results from reaction of CO2+ with several CO2 molecules. This reaction is not well understood but a mechanism involving stepwise ion polymerization followed by collision-induced decomposition of the complex to C2O4+ is suggested.

Phase nonreciprocity in an optical fiber interferometer due to acoustic emission

“…It has been demonstrated that the 0 ; is formed by the reaction, This not only accounts for the observation of 0; by Adamczyk et a1 (1972), but it is also consistent with the fact that a lower 0' cross section is observed by them than is estimated presently. Moreover, Schildcrout and Franklin (1969) demonstrate that 0' is lost by another process and find the reaction o++co2+co:+o consistent with their data. This is confirmed by the work of Mosesman and Huntress (1970).…”

“…The mechanism by which 0; is produced from CO, has been studied in high pressure mass spectrometers by Paulson et a1 (1966) and Schildcrout and Franklin (1969). It has been demonstrated that the 0 ; is formed by the reaction, This not only accounts for the observation of 0; by Adamczyk et a1 (1972), but it is also consistent with the fact that a lower 0' cross section is observed by them than is estimated presently.…”

“…Again the cross sections for these processes are large, Schildcrout and Franklin (1969), Fehsenfeld et a1 (1966), Schildcrout et al(1970. Since reaction (3) would give an apparent increase in the CO' cross section while (4) would produce a decrease and since there is considerable discrepancy in the cross sections measured for reaction (4), the effect of these reactions on the data of Adamczyk et a1 (1972) is less obvious.…”

Photoionization of CO2-CO-O2 mixtures. Formation and reactions of ion clusters

“…We cannot confirm or deny the occurrence of overall processes such as (5) which is quantitative for removal of the minor 0+ fragment ion from the system. Although we did not attempt to derive an accurate rate coefficient for this reaction, our decay curve for 0+ is consistent with rate constants in the range 0.8 to 1.2 X 10 -9 cm 3 /molecule-s reported for this process from other laboratories [3,8]. ·The O~ produced from the reaction of 0+ with CO2 reacts with CO2 at pressures greater than a few tenths of a torr to yield the (02 • CO2)+ association ion (where n > 2) at higher pressures, although higher order processes of this type were observed by Schildcrout and Franklin [8] in electron impact ionization experiments at pressures in the range from 0.05 to approximately 1 torr.…”

Reactions of (CO2)2+ and (CO)2+ association ions

“…Many of the measurements were deliberately taken in the presence of water collisionally desorbed within the reaction chamber, while the majority were taken under essentially dry conditions in order to minimize hydrated species in the reactant ion spectrum. With the exception of those experiments involving 0 2 as an additive, the contribution of 0 2 + formed in C02 by the reaction [7,[12][13][14][15] The first portion of this section deals specifically with the ion chemistry observed under various conditions in the presence of the additives chosen for study, including reaction mechanisms and product ion distributions. This is followed by a second segment which involves assignment of rate coefficients for the formation and reaction of cluster ions.…”